1. Field of the Invention
This invention pertains to a process for the separation of solid matter, from a suspension, via flotation, in a separating space wherein the suspension, during floatation undergoes a rotational movement, with this rotational movement being superimposed by an additional movement, the latter extending substantially in a direction of a rotational axis, and whereby the components undergoing flotation are moved radially inwardly. An apparatus for carrying out the process of the invention is also set forth.
2. Discussion of the Background of the Invention and Material Information
Processes of the above described type are utilized in order to separate at least a portion of the solid matter particles suspended in a suspension. The purpose therefore is either the removal of undesired component parts or the purification of dirty waste water. As is well known, during flotation, a foam or flotation sludge, containing the substances to be removed, is formed.
A typical application for the use of such a process is the treatment of a suspension made up of printed old waste paper, in which the printing color particles are already separated from the fibers so that the latter can be selectively removed via flotation (Deinking-Flotation).
Prior Art German Patent Publication DE-C-3 306 600 and cognate U.S. Pat. No. 4,560,474 disclose a flotation apparatus which already utilizes the acceleration field caused by the rotational movement of the suspension. The flotation foam is removed from the flotation apparatus via an upper outlet tube while the cleaned suspension exits at the bottom. This means a separation of the incoming stream, viewed axially, into oppositely directed partial streams. Such a stream conduction is also normally utilized in hydrocyclones and leads to an overproportional increase in centrifugal acceleration, toward the middle or center of the container, in the form of a so-called potential vortex.